DTC P0506

DTC P0506	IAC system RPM lower than expected
DETECTION CONDITION	The PCM compares the actual idle speed with the target idle speed when the engine is running. If the actual idle speed is lower than targeted by 100 rpm, the PCM determines that the IAC system RPM is lower than expected. Diagnostic support note This is a continuous monitor (CCM). The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA (Mode 2/Mode 12) is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	VSS malfunction Drive-by-wire control system malfunction A/C cut-off control malfunction Generator control system malfunction Intake-air line clogged Air cleaner clogged Throttle body clogged Purge solenoid valve malfunction IAT sensor malfunction ECT sensor malfunction APP sensor malfunction Eccentric shaft position sensor malfunction Insufficient compression Metering oil pump malfunction Engine oil malfunction Oil pressure decrease Oil passage malfunction Engine malfunction Fuel line pressure malfunction Fuel pump unit malfunction Pressure regulator (built-in fuel pump unit) malfunction PCM malfunction

IAC system RPM lower than expected

DETECTION CONDITION

The PCM compares the actual idle speed with the target idle speed when the engine is running. If the actual idle speed is lower than targeted by 100 rpm, the PCM determines that the IAC system RPM is lower than expected.

Diagnostic support note

This is a continuous monitor (CCM).
The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
FREEZE FRAME DATA (Mode 2/Mode 12) is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

VSS malfunction
Drive-by-wire control system malfunction
A/C cut-off control malfunction
Generator control system malfunction
Intake-air line clogged
- Air cleaner clogged
- Throttle body clogged
Purge solenoid valve malfunction
IAT sensor malfunction
ECT sensor malfunction
APP sensor malfunction
Eccentric shaft position sensor malfunction
Insufficient compression
- Metering oil pump malfunction
- Engine oil malfunction
- Oil pressure decrease
- Oil passage malfunction
- Engine malfunction
Fuel line pressure malfunction
- Fuel pump unit malfunction
- Pressure regulator (built-in fuel pump unit) malfunction
PCM malfunction

DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 12) HAS BEEN RECORDED Has the FREEZE FRAME DATA (Mode 12) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 12) on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE OR STORED DTC Turn the ignition switch off, then to the ON position (engine off). Verify the related PENDING CODE or stored DTCs. Are other DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE ).
3		No	Go to the next step.
4	VERIFY CURRENT INPUT SIGNAL STATUS OF VSS Start the engine. Access the VSS PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST ). Inspect the VSS PID. Is the PID normal? (See PCM INSPECTION ).	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part according to the inspection results, then go to Step 21.
5	INSPECT DRIVE-BY-WIRE CONTROL SYSTEM OPERATION Perform the Drive-by-wire Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 21.
5		No	Go to the next step.
6	INSPECT A/C MAGNETIC CLUTCH OPERATION Turn the blower motor switch off. Is the magnetic clutch still on?	Yes	Go to the "NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY ).
6		No	Go to the next step.
7	INSPECT GENERATOR CONTROL SYSTEM OPERATION Apply the electrical load at idle. Is the engine speed increased?	Yes	Go to the next step.
7		No	Repair or replace the wiring harness for a possible short to power supply, then go to Step 21.
8	INSPECT AIR CLEANER ELEMENT Remove the air cleaner element with the engine running. Is the engine speed increased?	Yes	Clean or replace the air cleaner element, then go to Step 21. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION ).
8		No	Go to the next step.
9	INSPECT THROTTLE BODY PASSAGE Remove the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION ). Is the throttle body clogged?	Yes	Clean the throttle body passage or replace the throttle body, then go to Step 21. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION ).
9		No	Go to the next step.
10	INSPECT PURGE SOLENOID VALVE Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION ). Is there any malfunction?	Yes	Replace the purge solenoid valve, then go to Step 21.
10		No	Go to the next step.
11	INSPECT EAT SENSOR Inspect the IAT sensor. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the MAF/IAT sensor, then go to Step 21. (See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION ).
11		No	Go to the next step.
12	INSPECT ECT SENSOR Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the ECT sensor, then go to Step 21. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION ).
12		No	Go to the next step.
13	INSPECT APP SENSOR Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the accelerator pedal, then go to Step 21. (See ACCELERATOR PEDAL REMOVAL/INSTALLATION ).
13		No	Go to the next step.
14	INSPECT ECCENTRIC SHAFT POSITION SENSOR Inspect the eccentric shaft position sensor. (See ECCENTRIC SHAFT POSITION SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the eccentric shaft position sensor, then go to Step 21. (See ECCENTRIC SHAFT POSITION SENSOR REMOVAL/INSTALLATION ).
14		No	Go to the next step.
15	INSPECT ENGINE COMPRESSION Inspect the engine compression. (See COMPRESSION INSPECTION ). Is there any malfunction?	Yes	Go to the next step.
15		No	Go to Step 20.
16	INSPECT METERING OIL PUMP Inspect the metering oil pump. (See METERING OIL PUMP INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine, then go to Step 21.
16		No	Go to the next step.
17	INSPECT ENGINE OIL CONDITION Inspect the engine oil condition. Is the engine oil condition normal?	Yes	Go to the next step.
17		No	Replace the engine oil. Overhaul or replace the engine, then go to Step 21.
18	INSPECT OIL PRESSURE Inspect the oil pressure. (See OIL PRESSURE INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine, then go to Step 21.
18		No	Go to the next step.
19	INSPECT OIL PASSAGE Inspect the oil pipe between metering oil pump and metering oil nozzle. Is there any malfunction?	Yes	Inspect for leakage or clogging in the engine oil passage. Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine, then go to Step 21.
19		No	Overhaul or replace the engine, then go to Step 21.
20	INSPECT FUEL LINE PRESSURE Perform the "FUEL LINE PRESSURE INSPECTION". (See FUEL LINE PRESSURE INSPECTION ). Is there any malfunction?	Yes	Replace the fuel pump unit, then go to the next step. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ).
20		No	Go to the next step.
21	VERIFY TROUBLESHOOTING OF DTC P0506 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE ). Start the engine. Perform the Pending Trouble Code Access Procedure. (See ON-BOARD DIAGNOSTIC TEST ). Is the PENDING CODE same as DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION ).
21		No	Go to the next step.
22	VERIFY AFTER REPAIR PROCEDURE. Perform the "AFTER REPAIR PROCEDURE ". (See AFTER REPAIR PROCEDURE ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE ).
22		No	DTC troubleshooting completed.